Method of reducing surface ignition requirements



3,@%,fi8l Patented May 21, 1963 3,00,681 METHOD 9F REDUCING URFACE IGNITION REQMENTS Ralph B. Thompson, Hinsdale, Joseph A. Chenicek, Prairie View, and Wayne J. Faust, Arlington Heights, 111., assignors, by mesne assignments, to Universal Oil Products Company, Des Plaines, 111., a corporation of Delaware No Drawing. Filed Feb. 13, 1958, Ser. No. 714,970

3 Claims. (CI. 44-76) This invention relates to a novel method of reducing surface ignition requirements in a spark ignition engine. The present application is a continuation-in-part of our copending application Serial No. 487,222, filed February 9, 1955, and now abandoned.

Recent studies in spark ignition engines have shown that abnormal combustion occurs in some cases and particularly when using high compression ratios. The abnormal combustion may take various forms and apparently results from deposits, within the combustion zone, of such properties that they cause ignition of the fuel, thus interfering with normal ignition by the spark plugs. The abnormal ignition may occur either before or after normal ignition initiated by the spark plugs, and may be observed as wild ping, rumble, knock, engine roughness, missing or after-firing (run-on).

It is believed that the abnormal ignition is caused by incandescent particles of combustion chamber deposits which are undergoing vigorous oxidation either on the combustion chamber walls or in the gaseous mixture. These incandescent particles ignite the fresh fuel-air mixture during the compression step and thus disrupt the normal ignition caused by the spark plugs. As will be noted, these phenomena are different from the knock caused by the use of a fuel of too low antiknock value, the latter being improved through the use of tetraethyl lead or other suitable antiknock agents. Because these phenomena are different, the methods of correcting them likewise are different. Furthermore, the use of tetraethyl lead may result in deposit formation and accumulation in the combustion zone, and these deposits may in turn be the cause, all or in part, of abnormal ignition. Thus, it is necessary to offset the ignition caused by such deposits.

In one embodiment, the present invention relates to a method of reducing surface ignition requirements in a spark ignition engine which comprises incorporating in the fuel supplied to said engine an additive of the fol lowing general formula:

where Ar is an aromatic radical, P is phosphorus, Y is sulfur or oxygen, and X is a halo, haloalkoxy or haloaryloxy radical.

The aromatic radical (Ar) preferably comprises a hen zene radical. In some cases, the aromatic radical may be a naphthalene radical. It is understood that the aromatic radical may contain hydrocarbon groups attached thereto as, for example, in such radicals as tolyl, Xylyl, trimethylphenyl, ethylphenyl, diethylphenyl, propylphenyl, dipropylphenyl, butylphenyl, dibutylphenyl, etc.

As hereinbefore set forth, X in the above general formula is a halo, haloalkoxy or haloaryloxy radical. Preferably this is a chloro, chloroalkoxy or cbloroaryloxy radical. In some cases the corresponding bromine compounds may be utilized and in still other cases the corresponding iodine or fluorine radicals may be employed but not necessarily with equivalent results. The chlorinecontaining compounds are generally less expensive and more readily available and for these reasons are preferred. In the interest of brevity, the present specifications will name only the chloro derivatives specifically in the following examples, but it is understood that the corresponding compounds containing the other halogens may be employed as hereinbefore set forth.

Where X is a chloro radical and Y is sulfur, representative compounds include benzene phosphorus thiodichloride, tolyl phosphorus thiodichloride, xylyl phosphorus thiodichloride, naphthyl phosphorus thiodichloride, etc. Where Y is oxygen, representative compounds include benzene phosphorus oxydichloride, tolyl phosphorus oxydichloride, xylyl phosphorus oxydichloride, naphthyl phosphorus oxydichloride, etc.

Where X is a chloroalkoxy and Y is oxygen, representative compounds include di-chloromethyl benzenephosphonate, di-chloroethyl benzenephosphonate, di-chloropropyl benzenephosphonate, di-chlorobutyl benzenephos phonate, di-chloroamyl benzenephosphonate, di-chlorohexyl benzenephosphonate, di-chloroheptyl benzenephosphonate, di-chlorooctyl benzenephosphonate, di-chlorononyl rbenzenephosphonate, di-cblorodecyl benzenephos phonate, etc., di-chloromethyl toluenephosphonate, dichlor-oethyl toluenephosphonate, di-chloropropyl toluenephosphonate, di-chlorobutyl toluenephosphonate, di-chloroamyl toiuenephosphonate, di-chlorohexyl toluenephosphonate, di-chloroheptyl toluenephosphonate, di-chlorooctyl toluenephosphonate, etc., di-chloromethyl xylenephosphonate, di-chloroethyl xylenephosphonate, di-chloropropyl Xylenephosphonate, di-chlorobutyl Xylenephosphonate, di-chloroamyl xylenephosphonate, di-chlorohexyl xylenephosphonate, di-chloroheptyl xylenephosphonate, di-chlorooctyl xylenephosphonate, etc. Where X is a chloroaryloxy radical, representative compounds include dichlorophenyl benzenephosphonate, di-chlorotolyl benzenephosphonate, di-chloroxylyl benzenephosphonate, etc., dichlorophenyl toluenephosphonate, di-chlorotolyl toluenephosphonate, di-chloroxylyl toluenephosphonate, etc., dichlorophenyl Xylenephosphonate, di-chlorotolyl xylenephosphonate, di-chloroxylyl xylenephosphonate, etc.

Where X in the above general formula is chloroalkoxy radical and Y is sulfur, representative compounds include dichloromethyl benzenethiophosphonate, di-chloroethyl benzenethiophosphonate, di-chloropropyl bcnzenthiophosphonate, dichlorobutyl benzenethiophosphonate, di chlororoamyl benzenethiophosphonate, di-chlorohexyl benzenethiophosph-onate, di-chloroheptyl benzenethiophosphonate, di-chlorooctyl benzenethiophosphonate, di-chlo- 'rononyl benzenethiophosphonate, di-chlonodecyl benzenethiophosphonate, etc., di-chloromethyl toluenethiophosphonate, di-chloroethyl toluenethio-phosphonate, di-chloropropyl toluenethiophosphonate, di-chlorobutyl toluenethiophosphonate, di-chloroamyl toluenethiophosphonate, di-ch-lorohexyl toluenethiophosphonate, di-chloroheptyl toluenethiophosphonate, di-chlorooctyl toluenethiophosphonate, etc., di-clrloromethyl Xylenethiophosphonate, dichloroethyl xylenethiophosphonate, di-chloropropyl xylenethiophosphonate, di-chlorobutyl xylenethiophosphonate, di-chloroaanyl Xylenethiophosphonate, di-chlorohexyl xylenethiophosphonate, di-chloroheptyl Xylenethiophosphonate, di-chlorooctyl xylenethiophosphonate, etc. Where X is a chloroaryloxy radical, representative compounds include di-chlorophenyl benzenethiophosp-honate, di chlorotolyl benzenethiophosphonate, di chloroxylyl benzenethiophosphonate, etc., di-chlorophenyl toluenethiophosphonate, di-chlorotolyl toluenethiophosphonate, di-chloroxylyl toluenethiophosphonate, etc., di-chlorophenyl Xylenethiophosphonate, di-chlorotolyl Xylenethiophosphonate, di-chloroxylyl Xylenethiophosphonate, etc;

"a 1951 Chrysler V-8 engine.

It is understood that numerous compounds may be used within the broad scope of the present invention but that these compounds are not necessarily equivalent. However, compounds Within the general formula hereinbefore set forth be effective in reducing surface ignition 'requirements.

The additive of the present invention will be used in a concentration suflicient to effect reduction in the surface ignition requirements caused by abnormal ignition. In general, the additive will be used in a concentration of from about 0.0001% to about 1% by volume of the gasoline and preferably from about 0.001% to about 0.1%. A-s'hereinbefore set forth, when used in gasoline containing tetraethyl lead or other antiknock agents, alone or along with the alkyl halides or polyhalides used as scavenging agents, it may be necessary to utilize i3. higher concentration of the additive of the present invention, which concentration may be calculated on the basis of theories of phosphorus. A theory of phosphorus is the amount necessary to combine chemically with the lead from tetraethyl lead to form Pb (PO4) Thus, for every 3 mols of lead, 2 mols of phosphorus are utilized. In any event, the concentration will be within the range hereinbefore set forth.

It is understood that the additive of the present invention may be incorporated in gasoline to be used in spark ignition engines which in turn may be utilized in land vehicles, marine vehicles, aircraft, etc. It also is understood that the additive of the present invention may be used along with other compounds added in gasoline for specific purposes including, for example, antiknock agents, oxidation inhibitors, metal suppressors, dyes, etc.

The following examples are introduced to illustrate further the novelty and utilityof the present invention but not with the intention of unduly limiting the same.

EXAMPLE I The data reported in this example were obtained in The gasoline used in this example was a commercial regular grade gasoline, having an A.P.I. gravity of about 63, a boiling range of 91- 406 F. and a TEL content of about 2 ml./ gallon. The gasoline had a Research Method octane number of 85 and a Motor Method octane number of 79.5.

The additive used in this example is benzene phosphorus thiodichloride. It was utilized in a concentration of 0.1% by volume (4.7 theories of phosphorus). The tests were continued until equilibrium was established in the octane requirement, and the octane requirement at the end of the test period to avoid after-firing was determined and is reported in the following table:

Table 1 Test sample (with Control sample (no additive) additive) 88 (no alter-firing observed with reference fuels as low as 88 ON.)

Iso-octane plus 1.6

Octane requirement TEL/gallon to eliminate afterfiring.

From the data in the above table, it will be noted that the additive of the present invention served to considerably reduce the after-firing tendency.

EXAMPLE II EXAMPLE III 7 The additive of this example is di-chloropropyl hen- 4 zenethiophosphonate and is used in a concentration of 0.5 theory of phosphorus. This additive is evaluated in a 1952 Pontiac engine (7.70:1 compression ratio) which is operated at 2000 revolutions per minute, 10 brake horse power, F. jacket temperature and a normal spark timing of 22 before top dead center at 2000 revolutions per minute. At 2 hour intervals the surface ignition requirement is determined by switching to a primary reference fuel of known octane number, retarding the spark to top dead center and holding the throttle at wide open position for several seconds while listening for surface-ignition noises. The ignition is cut momentarily to determine after-firing and then the engine is returned to normal conditions using the test fuel until the next 2 hour interval when, depending upon the requirement of the previous determination, another reference fuel of different octane number is utilized. The use of reference fuels of higher octane numbers in subsequent tests minimizes deposit disturbances from severe combustion reactions which otherwise might occur when a reference fuel of too low an octane number is used.

The gasoline used in this run is a paraflinic gasoline, containing 3 ml. of TEL/gallon and 3 pounds of an oxidation inhibitor comprising N,N'-di-sec-butyl-pphenylene diamine per 1000 barrels of gasoline, has an A.P.I. gravity of 60 F. of 63.2, a boiling range of 113- 380 F., Research Method octane numbers of 68.2 clear and 84.0 with 3 ml. of TEL/gallon, and Motor Method octane numbers of 66.7 clear and 82.3 with 3 ml. TEL/- gallon.

The surface ignition requirement is the octane number of the reference fuel required to eliminate any normal combustion noise, preignition knock, after-firing etc. When evaluated in the above manner, the reference fuel containing the additive has an average-equilibrium requirement of at least 5 octane numbers below that of a control sample of gasoline not containing the additive.

EXAMPLE IV This example describes a run similar to that set forth in Example III except that the additive used in this example is di-chl'oromethyl benzenephosphonate. It is used in a concentration of 1.6 theories of phosphorus. When evaluated in the manner described in Example III, this additive serves to considerably reduce the surface ignition requirements of the gasoline.

We claim as our invention:

1. Gasoline of reduced surface ignition requirements in a spark ignition engine containing from about 0.0001% to about 1% by volume of an aryl phosphorus thiodihalide.

2. Gasoline of reduced surface ignition requirements in a spark ignition engine containing from about 0.0001 to about 1% by volume of an aryl phosphorus thiodichloride.

3. Gasoline of reduced surface ignition requirements in a spark ignition engine containing from about 0.0001% to about 1% by volume of benzene phosphorus thiodichloride.

References Cited in the file of this patent UNITED STATES PATENTS France May 7, 1956 

1. GASOLINE OF REDUCED SURFACE IGNITION REQUIREMENTS IN A SPARK IGNITION ENGINE CONTAINING FROM ABOUT 0.0001% TO ABOUT 1% BY VOLUME OF AN ARYL PHOSPHORUS THIODIHALIDE. 